MRO Shop Capacity and Backlog Weeks Calculator
A shop with a growing backlog needs to know whether the problem is capacity, mix or waiting time. This calculator converts headcount, shifts, utilisation and standard hours into units per week and weeks of backlog.
Your numbers
Count only licensed or skilled staff who work on the units.
Share of paid hours charged to work orders. Typical shops range widely, use your own data.
Your results
A planning estimate using an average standard time. Real turn times depend on part availability, test equipment, skills mix and customer approval delays.
Units per week vs technicians per shift
Sweeps Technicians per shift from 1 to 30, holding your other inputs fixed.
Capacity view from live data
Optional review of building this calculation from your work order and labour data.
Optional. The tool and every export work without this. No spam.
How to use the calculator
Enter technicians per shift, paid hours per day, shifts, working days and your productive utilisation. Then add the average standard hours per unit, the current backlog and the average weekly arrivals. The results show productive hours per week, units completed per week, the net change in backlog each week and how many weeks it will take to clear. Use the slider to see how sensitive the answer is to utilisation, which is often the least understood input.
- Use utilisation from charged hours divided by paid hours
- Use an average standard time that reflects your real mix
- Enter arrivals as a typical week, not a peak
The formulas
Productive hours per week equals technicians times shifts times paid hours times days times utilisation. Units per week is productive hours divided by average standard hours. Net burn is units per week minus weekly arrivals. If net burn is positive, weeks to clear equals backlog divided by net burn. If arrivals equal or exceed capacity, the backlog does not clear and the tool shows zero for weeks to clear, so check the load percentage and the extra technician estimate.
Worked example and cautions
With eight technicians, one shift, eight hours, five days and 70 percent utilisation, productive hours are 224 per week. At 36 hours per unit that is about 6.2 units a week. If 12 units arrive each week, the shop is at roughly 193 percent of capacity and needs about eight more technicians per shift, or a lower standard time or higher utilisation, just to stand still. Averages hide mix: a few long overhauls can distort capacity, so run the tool separately for each unit family.
- Run it by product family
- Check standard times against actuals
- Remember that waiting for parts does not use labour hours
Frequently Asked Questions
What utilisation should I use?
Use your own figure: hours charged to work orders divided by paid hours over a representative period. It is lower than most people expect once training, meetings, waiting and rework are counted.
Why does the weeks to clear show zero?
The tool shows zero when new arrivals are equal to or higher than capacity, because the backlog would never clear. Check the load percentage and the extra technicians result to size the gap.
Should I use standard hours or actual hours?
Use actual average hours if standards are out of date. If actuals are much higher than standards, that is a finding in itself, and the standards, the estimating or the process should be reviewed.
Does this include waiting time for parts?
No. It only models labour capacity. A unit waiting for parts or approval still sits in the backlog but uses no hours, so total turn time can be much longer than the capacity calculation suggests.
If you want capacity checked against live work orders and labour data in your ERP, we can build a read-only view that does this calculation automatically.
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